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	 <4B2C80DD.9080005@garzik.org> <4B2D1CF3.4070106@gmail.com>
Date: Sat, 19 Dec 2009 14:37:12 -0800
Message-ID: <7c8826910912191437k4e1d93bap12874a6d6e0046d3@mail.gmail.com>
Subject: Re: 2.6.32 seemed to have broken nVidia MCP7A sata controller
From: Mike Cui <cuicui@gmail.com>
To: Robert Hancock <hancockrwd@gmail.com>
Cc: Jeff Garzik <jeff@garzik.org>, linux-ide@vger.kernel.org,
       LKML <linux-kernel@vger.kernel.org>
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Thanks, changing that one line fixed it. I can try to find an intel
motherboard sometime next week to see if it's the drive or the
controller.

On Sat, Dec 19, 2009 at 10:35 AM, Robert Hancock <hancockrwd@gmail.com> wrote:
> On 12/19/2009 01:29 AM, Jeff Garzik wrote:
>>
>> On 12/19/2009 01:13 AM, Mike Cui wrote:
>>>
>>> I have an nVidia MCP7A AHCI controller. I upgraded to 2.6.32.2 and my
>>> system deterministically freezes trying to mount file systems. Once in
>>> a while it will come back and finish booting after freezing for 1
>>> minute or 2. dmesg indicates that there were NCQ errors, but 2.6.31
>>> anb before has always worked flawlessly for me. What changed in
>>> 2.6.32? I will be more than happy to help track down this issue.
>>
>>> ata1.00: exception Emask 0x0 SAct 0x1 SErr 0x0 action 0x6 frozen
>>> ata1.00: cmd 61/08:00:4f:ad:03/00:00:00:00:00/40 tag 0 ncq 4096 out
>>> res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
>>> ata1: hard resetting link
>>> ata1: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
>>> ata1.00: configured for UDMA/133
>>> ata1.00: device reported invalid CHS sector 0
>>
>> Looks like things are timing out, and then go downhill from there. This
>> explanation of timeout gives some hints on possible causes:
>> http://ata.wiki.kernel.org/index.php/Libata_error_messages#Error_classes
>>
>> The ideal would be if you could bisect between 2.6.31 and 2.6.32, to see
>> if it's a software change that is the cause.
>>
>> Looking at drivers/ata/ahci.c history, the only thing that -might- cause
>> problems is 388539f3ff0cf1de926b03f94e1eec112358f74d ('git show $commit'
>> for full commit info and diff).
>
> I suspect that as well (it's the commit that adds FPDMA auto-activate on DMA
> setup FIS support). Your drive indicates it's supported but it's possible
> it's broken on that drive or the controller. If the drive doesn't set the
> activate bit in the DMA setup FIS properly or the controller doesn't respect
> it, then FPDMA requests will stall.
>
> Mike, can you try and revert that patch, or else just change this line in
> drivers/ata/ahci.c:
>
>                pi.flags |= ATA_FLAG_NCQ | ATA_FLAG_FPDMA_AA;
>
> to
>
>                pi.flags |= ATA_FLAG_NCQ;
>
> and rebuild and see if it works better?
>
> I tend to suspect the controller is the problem (I've got WD drives that
> work fine with AA on Intel AHCI, though it could be model-specific). I guess
> the only way to verify for sure which one it is would be if someone else had
> that particular drive model on a different AHCI controller and could verify
> if it worked with 2.6.32+ or not.
>
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